Magnetic recorder



Dec. 27, 1938.

W. P] PATRICK MAGNETIC RECORDER .Filed Aug. 24, 1936 2 Sheets-Sheet l w3% Z. M .5 M,

H nu I m 4 u i 2 .l i .n I

H W" K i w QM 1 2 w I H M. B l L" 9 0 8 M Wi flflllllfi 4 INVENTORM70202: Ri a/rick ATTORNEY Patented Dec. 27, 1938 UNITED STATES PATENTOFFICE This invention relates to magnetic recorders of a type adapted torecord electrical disturbances on wire and afterwards to reproduce thedisturbances which have thus been recorded on the wire.

' A'primary object of this invention is to provide a simple, efficientand satisfactory apparatus for handling recording wire in such a mannerthatit may be passed in either direction through one or more headscap'able of recording electrical disturbances on said wire or ofreproducing from said wire previously recorded electrical disturb--ances.

Another object of this invention is to provide apparatus for handlingrecording wire in such a manner that the speed of the wire through theheads is always constant and the tension of the wire is alwayssubstantially constant.

Another object is to provide means for passing wire thi iiughelectromagnetic heads and switch- 'ing the control from one head toanother in.

such a manner that when the recording of a series of electrical.disturbances is complete it will always be possible to start withoutdelay and repro-v duce the recorded series of disturbances.

Another object is.to provide a device oi this nature in which areproducing. mechanism can be made to follow very closely after arecording mechanism on a wire toireproduce electrical dis- 80 turbances.within a short period of time after they are recorded.

Another object is to provide a magnetic record in a' wire, which recordis substantially permanent in its nature and to further provide such arecord in a fine, flexible, non-bulky wire which may readily betransported irom place to place iorireproduction. x

Another object is to provide an electromagnetic recording andreproducing device embody- 40 mg a plurality of heads and a section ofwire devoted to the use of each head in such a manner that each sectionof wire is capable of being passed in either direction through itscorresponding head either for the purpose of recording on said wire orreproducing from said wire.

In magnetic recorders employing wire, dimv culty has'heretofore beenencountered in handling the wire and feeding the same through therecorder heads. Devices of this type employing spools or drums in-such amanner that the wire is wound from one spool or drum to another usuallyallow the wire to pile up on the spools or drums. With these devices itis diificult to 'keep the wire moving at a constant speed due to thefact that when wire is winding onto a drum it progressively increasesthe effective diameter onto which it is winding and when it is unwinding it progressively decreases this eiiective diameter. Also in deviceswhere fine wire is allowed to pile up 'on spools or drumsv it'isdifllcult to 5- maintain a' constant tension on the wire and there isdanger of the wire becoming tangled or, being bent so sharply that itmay be'broken. When recording is done on wire which is wound onto, andpiles up on, spools or drums it is usually l0 necessary, after therecording is finished, to rewind the wire before reproduction of therecorded matter can be commenced.

My present invention overcomes the objections hereinbetore pointed outby providing a method 15 of and means for handling the wire by winding,7

it in a single layer on a drum of large diameter,

and by passing said wire, or sections of said wire, through one or morerecording or reproducing heads without transferring said wire from one20 drum to another.

In this way vI am able to keep the velocity oi. the wire constant-avoidtangling and breakage, reproduce without delay matter which has justbeen recorded, and attain other objects not attained by usual methods.25

Other objects 01 this invention are to provide wire handling means'foruse with magnetic recording and reproducing devices of this nature whichare simple in construction, reliable and eiiicient in operation, notexpensive to manuiacture, not liable to get out of order and which areespecially well adapted for recording and reproducing audible sounds, asspeech, music, and the like.

Other and more specific objects will be appar- 35 ent from thefollowing'description taken in connection with the accompanyingdrawings.

In the drawings, Figure 1 is an elevation of a magnetic recording andreproducing device made I in accordance with this invention. {i

Fig. '2 is a plan view of the same. 1

Fig. 3 is a front elevation of said magnetic recording and reproducingdevice.

Fig. 4 is a view in cross section substantially on broken line 6-4 ofFig. 2. 45 Figs. 5 and 6 are somewhat diagrammatic plan .views ofmodified forms oi this device, Fig. 6, being partly broken away.

one end with a suitable groove IQ for the reception of a driving belt l5which is connected with an electric motor IS. The motor I6 is reversibleand may be capable of having its speed varied. The end frames I2 and 13are secured to a base l1 and preferably have their top portionsconnected by a transverse truss rod l8 which is positioned above thedrum I0. Another truss rod 19, which also serves as a guide, connectsthe two end frames l2 and I3 forwardly of the truss rod I8. Atransverselead screw 20 extends crosswise of the drum "ill just forwardly of thetruss rod l9 andis journaled in the end frames l2 and I3. A combinedtruss and indicator bar 2| extends crosswise between the two end framesl2 and 53 at the front of the drum II). An up right instrument board orpanel 22 is secured to the forward portions of the side frames l2 and 53adjacent the base l1. The base l1, panel 22, bar 2|, and rods l9 and I8cooperate with the end frames l2 and I3 to form a substantial and strongframe structure forthe machine.

The lead screw 20 is driven by a link belt 23 which passes overtwo'sprocket wheels 26 and 25 secured to the-lead screw 20 and the mainshaft il respectively. The sprocket wheel 24 is preferably of largerdiameter than the sprocket wheel 25, providing for a reduction inspeed-between the shaft and lead screw 20.

Two recording and reproducing heads, designated generally by numerals 26and 21, are mounted on the lead screw 20 and guide rod l9. These headsare adapted to have recording wires 8 and 9 passed therethrough, ashereinafter described, for the purpose of subjecting said wires toelectrical or electromagnetic forces to produce a record in said wiresor to reproduce from said Wires a record previously made, or to erase oreliminate and destroy a record previously made. As this presentinvention is concerned only with the method of and means for handlingthe record wire, it is not deemed necessary to illustrate and describethe electrical and electromagnetic details of these recording andreproducing heads in this application. Y

The recording and reproducing heads 26 and 21 are mounted on angleshaped bracket members 28 having notches 29 which fit over and areguided on the guide rod l9 and also having combined nut and hub portions30 which are internally threaded and engage with the lead screw 26,which lead screw extends through said nut portions. The nut portions 30also serve as bear ing members for sheaves 3| and 32. Two of the bracketmembers 28 are used in forming the mounting means for each head 26 and21. These two bracket members are supported in spaced apart relation bythe heads 26 and 21 and by the.

- the heads reach the ends of the recording wires 8 and 9 which movethrough the heads. Prefer-v ably a switch arm 65 is connected with thelead screw 26 by friction means 46 for operating a switch means 41. Whenlead screw 20 is rotating in one direction switch arm 65 will beyieldingly urged in a corresponding direction establishing acondition'of switch means 61 which will render one head 26 or 21operative and the other head' inoperative. When the direction ofrotation of the lead screw is reversed the condition of the heads asrespects operativeness and inoperativeness will be reversed by reason ofthe switch arm 35 being yieldingly urged in the other direction. Thisreversal of the operating condition of the two heads synchronously withreversal of the other parts occurs irrespective of whether the heads areconditioned for recording or reproducing.

I .also preferably provide a reversing switch means 48 supported on anadjusting screw 49 in a position where it will be engaged and operatedby any suitable part which moves with the heads 26 and 21. Thisadjustable reversing switch means preferably has a pointer 50 movableover indicator bar 2! to indicate the setting or adjustment of the same.For instance, if the pointer 50 is set at 3 on the indicator bar 2| itmay mean that it will take three minutes of operation for the heads tomove from a zero or starting position far enough to operate thereversing switch. The reversing switch 48 reverses the motor "5 andautomatically starts the heads moving in a reverse direction when it isoperated. As both heads move in synchronium only one reversing switch isneeded and this reversing switch may be manually adjusted to allow anyperiod of operation within the limits of the machine. When the reversingswitch 48 is in use the limit switch 35 at the right hand side of themachine will remain inoperative but in the event the reversing switchfails to operate properly this limit switch 35 will prevent damage tothe machine.

In the device illustrated in Figs. 1 to 4, I have shown two pieces ofrecording wire 8 and 9 wound on the drum I0. Each of these pieces ofrecording wire 6 and 9 has each end secured to the drum as indicated at1 and each winding of wire has sufficient slack to permit one loop ofthe wire to extend outwardly through the adjacent head and around thesheave connected with said head and back to the drum. The wire 8 extendsthrough the head 26 and around the sheave 3| and the wire 9 extendsthrough the head 21 and around the sheave 32. Obviously more heads andmore windings of wire may be provided, if desired.

Also it will be apparent that one continuous winding of wire of anydesired length on a single drum may be provided with one or more loopsfeeding through one or -more heads. In Fig. 5, I have shown, somewhatdiagrammatically a single piece of wire 36 wound on a drum 31 and havingthree loops 38, 39 and 40 passing through three recording andreproducing heads I, 42 and 43. Obviously more than three heads may beprovided if desired and the wire may be passed through each head. Thelead screw provides means for always moving the several heads in thesame direction at the same rate of speed. In

Fig. 6, I have shown two heads 5| and 52 positioned adjacent a drum inrelatively angularly offset positions as respects each other and bothhaving a recording wire 53 passed therethrough.

' Lead screws 54 and 55 are provided for the respective heads 5! and 52.By angularly offsetting the heads SI and 52 relative to each other it ispossible to have a reproducing head following at any desired intervalafter the recording head and repeating the record at any interval afterit is made. This makes it possible to provide delayed speech or adelayed repetition of any series of electrical disturbances;

The pitch of the lead screw and the driving speed of the same aredesigned to impart the correct longitudinal movement to the heads whenamuse the recording wire is wound in a single layer on the drum with theadjacent turns of wire lyingreproduction, it being possible to recordmore matter on a given length of wire for head phone reproduction thanfor loud speaker reproduction. I

When the wire is handled in the manner shown and herein before describedI am able to move the wire at a constant speed, to reduce wear andstrain on the wire to a minimum, to avoid undue tensions on the wire, toeliminate the danger of snarling and tangling the wire and to reduce thedanger of breaking the wire to a minimurm It will be apparent that it isdesirable to secure a constant even speed of the wire through the headsin order to obtain the best results.

In operation of the device shown in Figs. 1

h to 4 the machine is set up, as shown, with the same direction, forapproximately half of the period of time the particular piece ofrecording is to cover. The setting 'of the heads is then reversedpreferably by the switches 18 and ll so that the head which waspreviously recording will be de-energized and will not affect the wirepassing therethrough and the previously idle head will be causedto-record. The heads are then moved in the opposite direction backsubstantially Y to the location or slightly past the location where theywere at the commencement of the 'record ing, the head which wasde-energized and idle during the first half of the'movement making therecord during the last half of the movement and the head which made therecord duringthe first half of the recording period being deenergizedand idle during the last half of the recording period. The two heads,having been moved back to the starting position during the last'half ofthe recording period will be properly positioned so that by againreversing the direction of movement of these heads to move them in theoriginal direction and by changing certain electrical controls, notherein specifically described,

to cause the heads 26- and 21 to reproduce rather than record, the headwhich first recorded may be caused to immediately begin to reproducewhat it recorded. After the first head has traversed all of the wire onwhich it recorded the direction of movement and condition of the headsmay again be reversed by switches 48 and 41 andthe head -which did thelast half of the recording may be caused toreproduce what .it

recorded;

Each head is essentially provided with means, not illustrated, to eraseor eliminate from the wire all previous records just prior to making anew record in said wire. I a

By handling the recording wire in the manner herein shown and describedit is possible to record or reproduce with the wire moving-in eitherdirection through either head and to reproduce what has been recordedwithout any undesirable time delay between the time the recording iscompleted and the reproducing commenced. Also it is possible to transferfrom one head to another, at will, in recording and to easily followthese transfers in reproducing.

The foregoing description and accompanying drawings clearly disclose apreferred embodiment of my invention but it will be understood that thisdisclosure is merely illustrative and that such changes in the inventionmay be made as are fairly within the scope and spirit of the followingclaims. Y

I claim: I

1. In a magnetic recording and reproducing device, a rotatably mounteddrum; reversible driving means connected with said drum; anelectromagnetic head positioned adjacent said drum and clear of thedrum; means providing relative movement between the head and the drum ina direction longitudinally of the drum when the device is in operation;and a recording wire wound in a single layer on said drum, saidrecording wire having a loop portion passing off of said drum andthrough said head and back onto said drum whereby said recording'wiremay be moved in either direction through said head by rotation of saiddrum.

2. In a magnetic recording and reproducingdrum, said recording wirehaving a loop por- 1 tion passing off of said drum and through said headand back onto said drum whereby without removing said wire from saiddrum, substantially the entire length of said recording 'wlre may bemoved in either direction through said head by rotation of said drum,and means providing relative movement between said head and said drum ina direction longitudinally of the drum when the device is in operationmaintaining said head always in alignment with said loop portion of wireas said loop portion travels longitudinally of the drum. I

3. Ina magnetic recording and reproducing de- J vice, a rotatablymounted drum; reversible driving means connected with said drum; aplurality of recording and reproducing heads positioned 'near said drum;a recording wire wound on said drum and having both ends secured to saiddrum, said wire having a plurality of loop portions each passing off ofthe drum and through one of the respective recording and reproducingheads and back onto the drum; and means providing relative movementbetween said heads and said drum in a direction longitudinally of thedrum when the device is in operation maintaining said heads always insubstantialalignment with said loop portions as said loop portionstravel longitudinally of the drum.

4. In a magnetic recording and reproducing device, a rotatably mounteddrum; a recording and reproducing head positioned near said drum;

drum; a recording wire wound in a single layer on said drum and havingboth the ends thereof se- 76 cured to said drum said recording wirehaving sufficient slaclmess to provide a loop portion extending awayfrom the drum and through the head; and means for moving said,headlengthwise relative to said drum in directions parallel to the axis ofthe drum, said head moving means being synchronized with said drumdriving means whereby said head and the loop portion of said' wire aresimultaneously moved in the same direction at substantially the samerate of speed.

5. In a magnetic recording and reproducing device, a rotatably mounteddrum, two transversely spaced apart recording and reproducing headspositioned near said drum; reversible driving means connected with saiddrum; recording wire means wound in a single. layer on said drum andhaving the ends thereof secured to said drum said recording wire meanshaving sufficient slackness to provide two loop portions extending awayfrom the drum and through the respective heads; and means forsimultaneously moving said two heads lengthwise relativeto said drum.

6. In a magnetic recording and reproducing device, a rotatably mounteddrum; a plurality of transversely spaced apart recording and reproducingheads positioned alongside of said drum; recording wire means wound in asingle layer on said drum and having a plurality of loop portionsextending away from the drum and through the respective heads andmovable through said heads by rotation of saiddrum; reversible drumrotating means connected with said drum; and means for simultaneouslymoving all of said heads lengthwise relative to said drum in directionsparallel to the axis of said drum, said head moving means beingsynchronized with said drum rotating means whereby said heads and theloop portions of said wire are simultaneously moved in the samedirections at substantially the same rate of speed and a section of saidwire is passed in either direction through each of said heads withoutremoving said wire from said drum.

7. In a magnetic recording and reproducing device, a rotatable mounteddrum; a lead screw positioned alongside of said drumparallel to the axisthereof; a recording and reproducing head mounted on said lead screw;recording wire means wound in a single layer on said drum and having itsrespective ends secured to said drum, said recording wire means having aloop portion extending away from the drum and through the head andmovable through said head by rotation of said drum; reversible drumrotating means connected with said drum; and lead screw driving meansconnected with said drum driving means for moving said head indirections parallel to the axis of said drum, said lead screw drivingmeans being synchronized with said drum rotating means whereby said headand the loop vice, a rotatably mounted drum; a recording and reproducinghead positioned near said drum; reversible driving means connected withsaid drum; a recording wire wound on said drum and having its endportions secured to said drum, said wire having a loop portion passingthrough said head; means synchronized with said drum rotating means formoving said recording head in directions parallel with the axis of saiddrum; control devices operated by said head moving means forsimultaneously reversing the direction of rotation of said drum and thedirection of movement of said head; and adjusting means connected withsaid control devices whereby said control devices may be selectivelypositioned for operation when said head has reached any pre determinedlocation in its travel.

WILLIAM P. PATRICK.

